U.S. patent number 4,537,285 [Application Number 06/483,941] was granted by the patent office on 1985-08-27 for conveyor lubricating apparatus.
Invention is credited to Patrick A. Brown, William C. Murphy.
United States Patent |
4,537,285 |
Brown , et al. |
August 27, 1985 |
Conveyor lubricating apparatus
Abstract
A conveyor lubrication apparatus includes a counter for
energizing lubrication devices once for each predetermined number
of cycles of the conveyor past a lubrication station. Timers
energized by the counter activate control valves for a
predetermined period of time to supply lubricant to parts of the
conveyor as each part reaches the lubrication station. A current
sense circuit detects current flow to the control valves and
energizes the central lubricant supply pump to pressurize the
lubricant flow lines for a predetermined period of time, at the end
of which the pump is de-energized until the next control valve is
energized. A pressure sensor is disposed in the lubricant flow
lines to detect a low pressure level and causes the pump to be
de-energized and an alarm to be activated.
Inventors: |
Brown; Patrick A. (Fremont,
MI), Murphy; William C. (Fremont, MI) |
Family
ID: |
23922118 |
Appl.
No.: |
06/483,941 |
Filed: |
April 11, 1983 |
Current U.S.
Class: |
184/15.2;
184/6.1; 184/6.28; 184/6.4; 198/500 |
Current CPC
Class: |
B65G
45/08 (20130101); F16N 29/00 (20130101); F16N
7/38 (20130101); F16N 2230/10 (20130101) |
Current International
Class: |
B65G
45/00 (20060101); B65G 45/08 (20060101); F16N
29/00 (20060101); F16N 7/00 (20060101); F16N
7/38 (20060101); F16N 029/00 () |
Field of
Search: |
;184/1C,6,6.1,6.4,6.28,7R,15.1,15.2,15.3,64 ;198/500 ;361/170,187
;417/317 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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|
|
|
|
0049598 |
|
Apr 1982 |
|
EP |
|
2229990 |
|
Jun 1974 |
|
DE |
|
2265037 |
|
Feb 1976 |
|
DE |
|
2716559 |
|
Oct 1977 |
|
DE |
|
Primary Examiner: Brown; David H.
Assistant Examiner: Griffiths; John E.
Attorney, Agent or Firm: Basile, Weintraub & Hanlon
Claims
We claim:
1. A conveyor lubrication apparatus for a conveyor having a
plurality of interconnected and movable elements arranged in a
continuous, closed loop and movable in successive cycles about the
loop and a central lubricant supply reservoir pressurized by a
pump, the conveyor lubrication apparatus comprising;
fluid flow conduits connected to the central pumpdriven lubricant
supply reservoir;
valve means disposed in fluid flow communication with the central
lubricant supply reservoir by the fluid flow conduits and located
in proximity with the conveyor for controlling the application of
lubricant to the conveyor;
control means for controlling the energization of the valve means
once for each pre-determined number of cycles of the conveyor past
the lubrication apparatus, the control means including;
first detector means for detecting the presence of one particular
element of the conveyor at the lubrication apparatus;
programmable counter means, responsive to the first detector means,
for counting the number of cycles of the one particular element of
the conveyor past the lubrication apparatus;
program means, connected as inputs to the counter means, for
inputting count information to the counter means specifying the
number of complete cycles of the conveyor past the lubrication
apparatus between lubrication application;
the counter means providing an output specifying the application of
lubricant to the conveyor during one cycle of the conveyor past the
lubrication apparatus once for each programmed number of cycles of
the conveyor past the lubrication apparatus;
second detector means for detecting the presence of the elements of
the conveyor at the lubrication apparatus;
first timer means, responsive to the output of the counter means
and the second detector means for energizing the valve means for a
first pre-determined period of time to apply lubricant to the
conveyor as the conveyor passes through the lubrication
apparatus;
means for sensing current flow to the valve means;
second timer means, responsive to the output of the current sensing
means, for providing an output signal for a second pre-determined
period of time after current is initially applied to the valve
means; and
first switch means, responsive to the output of the second timer
means, for conencting electrical power to the pump in the central
lubricant supply reservoir only for the second pre-determined time
period.
2. The conveyor lubrication apparatus of claim 1 further
including:
pressure sensing means for sensing the fluid pressure within the
fluid flow conduits, the pressure sensing means providing an output
when the pressure within the fluid flow conduits falls below a
pre-determined level; and
the first switch means being responsive to the output of the
pressure sensing means for disconnecting electrical power to the
pump when the pressure falls below the predetermined level.
3. The conveyor lubrication apparatus of the claim 2 further
including:
alarm means;
second switch means, responsive to the output of the pressure
sensing means, for connecting electrical power to the alarm means
when the pressure has fallen below a predetermined level.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates, in general, to conveyors and, more
specifically, to automatic conveyor lubrication apparatus.
2. Description of the Prior Art
A common method of moving parts or components along a manufacturing
assembly line is by means of overhead conveyors. Such conveyors are
formed of a number of wheeled trolleys which ride along a guideway
or track in a continuous closed loop. The trolleys are
interconnected by a chain formed of a number of connected links.
The parts or components are suspended from the trolley.
The conveyor chain and wheeled trolleys include many interconnected
parts which require periodic lubrication. These parts include the
trolley roller bearings and the joined parts of the numerous chain
links. Automated lubrication equipment has been devised to
eliminate the need for manual lubrication and to provide a
consistently precise quantity of lubricant to the various portions
of the conveyor so as to prevent wear and the problems associated
with overlubrication.
Such automated conveyor lubrication systems include a central
pump-driven lubrication tank which provides lubricant under
pressure throughout flow lines. Control valves or other fluid flow
metering devices are energized at the appropriate time to dispense
a predetermined quantity of lubricant to the desired element of the
conveyor. Typically, switches, such as photo, limit or proximity
switches, detect each chain link or trolley of the conveyor as it
arrives at the lubrication station and are operative through
electric control equipment to energize the valves for the
application of lubricant to the conveyor parts.
Since conveyors typically move at a slow rate of speed along a
predetermined path within a manufacturing plant, it is oftentimes
unnecessary to lubricate the parts or elements of the conveyor on
each cycle as this could result in overlubrication which is costly
and could cause excess lubricant to drip from the conveyor onto the
parts suspended therefrom or the underlying plant area. Thus,
counter apparatus as disclosed in U.S. Pat. No. 4,064,970 have been
devised to count the number of cycles of the conveyor past the
lubrication station and to activate the lubrication apparatus once
for each of a predetermined number of cycles of the conveyor. In
this manner, all of the desired parts or elements of the conveyor
are lubricated once for every predetermined number of cycles of the
conveyor past the lubrication station.
However, such previously devised conveyor lubrication apparatus
have not been without drawbacks. The counters utilized to provide
lubrication once for every predetermined number of cycles of the
conveyor past a lubrication station are not easily resetable to
provide different frequencies of lubrication. Furthermore, even
though the lubrication is applied only once for every predetermined
number of cycles of the conveyor past the lubrication station, the
central lubricant pump is continually maintained in an energized
state in order to maintain pressure within the lubrication lines.
This wastes power and places undue wear on the lubrication pump
since the lubricant is dispensed only infrequently.
Thus, it would be desirable to provide a conveyor lubrication
apparatus which overcomes the problems associated with previously
devised conveyor lubrication apparatus. It would also be desirable
to provide a conveyor lubrication apparatus which is easily
programmable so as to provide any desired frequency of lubrication
of the various elements of the conveyor. It would also be desirable
to provide a conveyor lubrication apparatus in which the centrally
located lubrication pump is de-energized between non lubrication
cycles of the conveyor.
SUMMARY OF THE INVENTION
There is disclosed a unique conveyor lubrication apparatus for
automatically lubricating preselected elements or components of a
conveyor. The lubrication apparatus includes a central pump-driven
lubrication reservoir or tank which supplies lubricant through
lubricant flow lines to a plurality of controllable valve means
which are mounted in a lubrication station adjacent to the
conveyor.
A plurality of detector means, such as limit switches, are mounted
in the lubrication station for respectively detecting the presence
of the start point of the conveyor as well as the presence of each
element, such as the movable trolleys or interconnected chain
links, at the lubrication station. Counter means responsive to the
presence of the first element of the conveyor at the lubrication
station energizes the conveyor lubrication apparatus for the
application of lubricant to each part of the conveyor once for
every predetermined number of cycles of the conveyor past the
lubrication station. The counter means is programmable by means of
settable switches so as to provide any desired frequency of
lubrication application to the conveyor.
Timer means responsive to the counter means and the detector
switches energize the control valves at predetermined times to
apply lubricant to each part of the conveyor as each part passes
the lubrication station. A unique current sense circuit is provided
for detecting the energization of any of the control valves. The
current sense circuit is adapted to instantaneously energize the
central pump to pressurize the lubrication flow lines for a
predetermined period of time, at the end of which the pump is
de-energized until a subsequent control valve is energized.
A pressure sensor is disposed in the lubrication flow lines for
detecting low pressure levels. The pressure sensor is electrically
connected to the central pump and causes the pump to be
de-energized and an alarm to be activated in the event that a low
pressure level is detected.
The unique conveyor lubrication apparatus of the present invention
affords many advantages over previously devised conveyor
lubrication apparatus. For one, the present conveyor lubrication
apparatus is easily programmable so as to provide lubrication of
the various elements or part of the conveyor at any desired
frequency interval. The conveyor lubrication apparatus of the
present invention also includes a unique current sense circuit
which detects when any of the lubrication control valves have been
energized. The current sense circuit instantaneously energizes the
central pump so as to pressurize the lubrication flow lines and,
more importantly, de-energizes the pump a predetermined amount of
time after a control valve has been energized. In this manner,
unnecessary energization of the pump is eliminated which minimizes
wear on the pump. The current sense circuit also provides energy
savings since the pump is de-energized during nonlubrication cycles
of the conveyor. Finally, the conveyor lubrication apparatus of the
present invention includes a pressure sensor which is uniquely
disposed in the lubrication flow lines for detecting low pressure
levels. If a low pressure level is detected, the pressure sensor
through appropriate control circuitry causes the pump to be
de-energized and an alarm to be activated to immediately indicate
the occurrence of a low pressure condition.
BRIEF DESCRIPTION OF THE DRAWING
The various features, advantages and other uses of the present
invention will become more apparent by referring to the following
detailed description and drawing in which:
FIG. 1 is an exploded, perspective view of a conveyor lubrication
apparatus constructed in accordance with the teachings of the
present invention;
FIG. 2 is a perspective view of a conveyor which may be used with
the conveyor lubrication apparatus of the present invention;
FIG. 3 is an end view of the conveyor illustrated in FIG. 2;
FIG. 4 is a schematic diagram of the conveyor lubrication apparatus
shown in FIG. 1 depicting the lubrication flow lines and electrical
wiring connections;
FIG. 5 is a circuit diagram of the power control unit illustrated
in FIG. 4;
FIG. 6 is a circuit diagram of the counter circuit illustrated in
FIG. 4; and
FIG. 7 is a circuit diagram of the timer circuit illustrated in
FIG. 4.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Throughout the following description and drawing, an identical
reference number is used to refer to the same component shown in
multiple figures of the drawing.
Referring now to the drawing, and FIGS. 1, 2 and 3 in particular,
there is illustrated a conveyor lubrication apparatus 10 which is
operative to automatically lubricate various elements or parts of a
movable conveyor, a portion of which is illustrated in FIGS. 2 and
3 and denoted in general by reference number 20.
By way of example only, the conveyor 20 is in the form of a
continuous closed-loop path having an elongated continuous track or
guideway 22. Preferably, the track or guideway 22 is in the form of
an I-beam having spaced, horizontally extending legs 24 and 26
which are interconnected by a vertical intermediate web portion 28.
The lower horizontal leg 26 forms a track for a plurality of
trolleys 30 which move therealong. Each of the trolleys 30 includes
two rollers or wheels 32 and 34 which ride along the horizontal leg
26 of the I-beam 22 on opposite sides of the intermediate web
28.
Arms 36 and 38 are connected to and depend downward from each of
the rollers 32 and 34, respectively, and are interconnected at a
lower end by a cross bar 37. A hanger 43 is connected to the cross
bar 37 on each trolley 30 for supporting parts or components
therefrom.
A chain 40 formed of a plurality of interconnected links 41 and 42
connects each of the trolleys 30. Alternating links 42 are disposed
about the hangers 43 and transmit driving force through the hangers
43 to the trolleys 30 to cause movement of the trolleys 30 as the
chain 40 is driven in a conventional manner.
As is well known, the conveyor 20 includes a plurality of movable
parts which are subject to wear. These parts typically include the
bearings of each roller 32 as well as the interconnected portions
of the conveyor links 41 and 42. Thus, it is necessary that these
parts be lubricated in order to prevent undue wear. The conveyor
apparatus 10 of the present invention is constructed to provide
automatic lubrication of selected elements or parts of the conveyor
20, such as the trolley 32 bearings, as well as the interconnected
portions of the conveyor links 41 and 42. The conveyor lubrication
apparatus 10, as shown in FIG. 1 and schematically in FIG. 4,
includes a lubrication station 50 which is mounted at one point
along the conveyor 20. Lubricant is supplied to the station 50 from
a remotely located central lubricant tank or reservoir 52. A motor
driven pump 54 is mounted within the reservoir 52 for pressurizing
lubricant flow lines 56 extending from the central tank 52 to the
lubrication station 50.
As shown in FIG. 1, the lubrication station 50 includes a frame or
support structure 58 on which the various control components of the
conveyor lubrication apparatus 10 are mounted. The frame 58
includes an elongated tubular member which is formed with two
spaced, horizontally extending upper leg portions 60 and 62,
depending vertical sections 64 and 66 and a horizontal
interconnecting base portion 68. The upper leg portions 60 and 62
are adapted to be securely mounted to the top surface of the upper
leg 24 of the conveyor track 22 by means of welding or other
fasteners. The depending vertical sections 64 and 66 and the
interconnecting base portion 68 extend away and downward from the
track 22 and provide support structure for the various components
of the conveyor apparatus 10.
By way of example, the conveyor lubrication apparatus 10 is
configured for lubricating the trolley roller 32 bearings as well
as the interconnected portions of the conveyor links 41 and 42. It
will be understood, however, that other portions of the conveyor 20
may also be lubricated if necessary.
Lubrication of the trolley 30 bearings 32 is provided by a
controllable valve means, such as a solenoid-operated valve 70. The
valve 70 is mounted on a strap 72 which is affixed to and extends
between the upper leg portions 60 and 62 of the support frame 58. A
pair of lubricant flow tubes, such as capillary tubes 74 and 76,
extend from the valve 70 and have an open end disposed in proximity
with the trolley 30 bearings as each trolley 30 passes the
lubrication station 50.
A second controllable valve means 78 is also mounted on the strap
72 of the frame 58. A pair of capillary supply tubes 80 and 82
extend from the valve 78 and are disposed such that the open ends
are located in proximity with the interconnected portions of the
conveyor chain 50 as each interconnected portion passes the
lubrication station 50. Each of the valves 70 and 78 is disposed in
fluid communication with the central lubricant tank 52 by means of
lubricant flow lines 56, as shown in FIG. 4.
The conveyor lubrication apparatus 10 is designed to provide
lubricant to selected elements or parts of the conveyor 20 once for
every predetermined number of cycles of the conveyor 20 past the
lubrication station 50. Accordingly, it is necessary to detect when
the selected elements or parts of the conveyor reach the
lubrication station 50. In a preferred embodiment, first, second
and third detector means 84, 86 and 88, respectively, are mounted
on the support frame 58. Each of the detector means 84, 86 and 88
has a movable detector arm 90 mounted thereon which is adapted to
be engaged by a selected portion of the conveyor 20 so as to switch
the electric contacts of each limit switch and provide an
electrical signal indicating that the selected element or part of
the conveyor 20 has reached the lubrication station 50.
The controllable valves 70 and 78, as well as the first, second and
third detector means or switches 84, 86 and 88, respectively, are
electrically connected to a lube control unit 92 which is mounted
on the support frame 58. The lube control unit 92 includes the
circuitry used to selectively activate the valves 70 and 78 to
apply lubrication to the desired parts of the conveyor 20.
The conveyor lubrication apparatus 10 also includes a power control
unit 94 as shown in FIG. 4, and in greater detail in FIG. 5 which
may be mounted at the lubrication station 50, or, preferably,
located adjacent to the central lubrication tank 52. The power
control unit 94 houses the circuitry and control equipment used to
energize the pump 54 and pressurize the lubricant flow lines 56. In
the power control unit 94, a main disconnect switch 96 is provided
for activating the conveyor lubrication apparatus 10 of the present
invention. A transformer 98 is connected to the switch 96 and
transforms the 120 VAC input voltage to 24 VAC. A rectifying bridge
100 and a filter 102 are connected to the secondary winding of the
transformer 98.
Each of the control valves 70 and 78 is connected to the secondary
winding of the transformer 98. Current sense means, denoted in
general by reference number 104, is provided for sensing when
either of the control valves 70 or 78 is energized. The current
sense means 104 includes a hand-wound coil 106 which is preferably
formed of 115 turns of number 30 wire. The coil 106 senses current
flow to any of the control valves 70 and 78, as will be described
in greater detail hereafter, and is operative to close the contact
of a reed relay 108. The contact of the reed relay 108 is connected
to the input of a timer 110 and activates the timer 110 when
current flow is detected to any given control valve 70 or 78.
Upon energization, the output of the timer 110 will switch to a
high voltage level. The output of the timer 110 is connected as an
input to a NAND gate 112, the output of which is connected to the
base electrode of a transistor 114. The output of the timer 110
will remain in the high state for a predetermined period of time
which is selectable by utilizing appropriate values for the
resistor and the capacitor connected to the input of the timer
110.
A second input to the NAND gate 112 is normally in a high state
such that when the output of the timer 110 goes to a high state,
the output of the NAND gate 112 will go low which will drive the
transistor 114 into conduction and cause current flow to and
energization of a relay coil 116. The output contact 118 of the
relay coil 116 is connected between the source of electrical power
and the pump 54 and switches states so as to supply electrical
power to the pump 54 when the relay 116 is energized. In this
manner, the pump 54 pressurizes the lubricant flow lines 56 and
supplies lubricant to each of the control valves 70 and 78.
Turning now to FIGS. 6 and 7, there is depicted the control means
which is operative to selectively energize the control valves 70
and 78 to apply lubrication to the predetermined or parts of the
conveyor 20. As shown in FIG. 6, the lube control unit 92 includes
a counter means 130 which is operative to count the number of
cycles of the lead element of the conveyor 20 past the lubrication
station 50. The counter means 130 is responsive to and receives as
an input the output of the second detector means or switch 86. As
described above, the second detector means 86 is adapted to detect
the presence of the lead or first element of the conveyor 20 each
time it passes the lubrication station 50. The detector arm 90 on
the second detector switch 86 is engaged by an arm or dog 33, see
FIG. 2, attached to the lead trolley 30 of the conveyor 20 so as to
be activated once for each cycle of the lead trolley 30 past the
lubrication station 50.
The counter means 130 includes a bridge rectifying circuit 132 and
filter network 134 which transforms the 24 VAC input power to the
low level voltage required by the electronic components utilized in
the counter means 130.
The output of the second detector means or switch 86 is input
through inverters 136 to a binary counter 137 which is formed of
two serially connected 4-bit counters 138 and 140. The counters 138
and 140 also receive as inputs a plurality of progammable switches
141. Preferably the switches 141 are input in two groups of four to
the counters 138 and 140 so as to provide the capability of
preprogramming any count between 0 and 255 into the serially
connected counters 138 and 140.
The counters 138 and 140 are adapted to count down one count from
the preprogrammed count once for each energization of the second
detector means 86 which corresponds to one cycle of the lead
element or trolley 30 of the conveyor 20 past the lubrication
station 50. When the counters 138 and 140 count down to 0, all of
the outputs of the counters 138 and 140, which are connected as
inputs to a NAND gate 142, will be in a high state which drive the
output of the NAND gate 142 low. This signal is passed through
inverters 144 and 149 and energizes the coil of a relay 146. A
contact 148, shown in FIG. 7, is responsive to the energization of
the relay coil 146 and is operative to energize the timer means, as
will be described in greater detail hereafter. The output of the
NAND gate 142 is also reapplied to the counter elements 138 and
140, when the counters reach 0, to reload the preprogrammed count
set by the switches 142 back into the counters 138 and 140.
As shown in FIG. 4, the lube control unit 92 of the present
invention includes identical timer means 150 and 151 which are
asscoiated with each control valve 70 and 78, respectively. As each
of the timer means 150 and 151 is identical, the following
description is provided only for the timer 150 assoicated with
valve 70. As shown in FIG. 7, the timer means 150 is responsive to
the output of the first detector means or switch 84 (timer means
151 is responsive to the third detector means 88). The timer means
150 is operative to control the energization of the valve 70 which
applies lubricant to the bearings 32 of each trolley 30 when the
trolley 30 reaches the lubrication station 50. 24 VAC input power
is supplied to the timer means 150 through the contact 148
energized by the output of the counter 130.
A rectifying bridge 152 and filter network 154 are provided to
provide the appropriate voltage levels used to drive the timer 150.
When the counter 130 has been activated lubricant will be applied
to each element or part of the conveyor 20 during the next cycle of
the conveyor 20 past the lubrication station 50. Closure of the
second detector means or switch 86, which closes when each trolley
30 reaches the lubrication station 50, will energize a timer 156 to
provide an output signal having a predetermined time period. The
time interval of the timer 156 is selected by means of a
potentiometer 158 so as to provide any desired time, such as
between 0 and 1 seconds, for example. The output of the timer 156
is connected to the solenoid coil of the valve 70 and is operative
to energize the valve 70 to apply lubricant to the trolley 30
bearing 32 for the selected time interval. The valve 70 will be
energized by the timer 156 when each trolley 30 reaches the
lubrication station 50 as indicated by the closure of the second
detector means 86. Furthermore, energization of any valve 70 or 78
will cause current flow through the solenoid coil of the valve
which will be detected by the current sense means 104 which
energizes the central supply pump 54 to pressurize the lubricant
flow lines 56. When each trolley 30 of the conveyor 20 has passed
the lubrication station 50 and has been lubricated, the counter
means 130 will be reset such that input power is no longer applied
to the timer means 150.
In operation, the counter means 130 can be programmed to provide
any desired frequency of lubrication to the conveyor 20. For
exampale, the counter means 130 may be programmed to provide
lubricant to each element or part of the conveyor 20 once for every
five cycles of the conveyor 20 past the lubrication station 50.
Thus, when the lead element of the conveyor 20 reaches the
lubrication station 50 on the fifth cycle, the output of the
counter 130 will be energized to apply power to and activate each
of the timer means 150. As each element of the conveyor 20 reaches
the lubrication station 50, as detected by the second and third
detector switches 86 and 88, the solenoid valves 70 and 78 will be
energized by each timer means 150 for a predetermined period of
time to selectively apply lubricant to the trolley 30 bearing and
the interconnected portions of the conveyor chain links 42. When
the lead element of the conveyor returns to the lubrication station
50 on its next cycle, the counter means 130 will be reloaded with
new count information and lubrication will be terminated.
As shown in FIG. 4, the conveyor lubrication apparatus 10 also
includes a pressure sensor 160 which is disposed in the lubricant
flow lines 56 and is adapted to detect the pressure within the flow
lines 56. The pressure sensor 160, which may be any conventional
pressure switch, is pre-set for a predetermined pressure and
provides an output signal when the pressure within the lubricant
flow lines 56 falls below the pre-set pressure. The output signal
from the pressure sensor 160 is input to a flip-flop or latch
circuit 162, shown in FIG. 5. Thus, when the pressure sensor 160
provides an output indicating a low pressure level within the fluid
flow lines 56, the output of the flip-flop 162 will be driven to a
low level which, through the NAND gate 112, prevents conduction of
the transistor 114 and de-energizes the relay 116. This causes the
contact 118 of the relay coil 116 to move to an open state thereby
disconnecting electrical power from and de-energizing the pump 54.
The pump 54 will remain de-energized until power to the control
unit 94 is turned off and then back on.
The output of the flip-flop 162 also drives two serially connected
transistors 164 and 166 into conduction. This will supply current
to an alarm means denoted in general by reference number 168. The
alarm means 168 may comprise any alarm device and preferably
includes both visual and audible alarms. A low pressure condition
could occur when a lubricant flow line 56 has been ruptured, one of
the control valves 70 or 78 has stuck in an open position or the
lubricant in the central tank 52 has reached a low level.
Thus, there has been described a unique conveyor lubrication
apparatus which is operative to provide lubrication to selected
elements of a conveyor once for every predetermined number of
cycles of the conveyor past the lubrication station. The
lubrication apparatus of the present invention is programmable so
as to provide any desired lubrication cycle frequency.
The conveyor lubrication apparatus of the present invention also
includes a unique current sense circuit which detects current flow
to any of the lubricant control valves and is operative to energize
the central lubricant tank pump to provide lubricant to the control
valves for a predetermined period of time. At the expiration of the
predetermined time period, the pump is de-energized until the next
control valve is activated, thereby minimizing electrical power
usage and extending the useful life of the pump.
* * * * *